Photogrammetry
The science and technique of obtaining reliable measurements and 3D models from overlapping photographs — the standard method for heritage surface documentation at scale.
Photogrammetry is the science of making measurements from photographs. In heritage documentation, it is primarily used to derive three-dimensional geometry from overlapping digital photographs through a process called Structure from Motion (SfM). The output can include dense point clouds, textured 3D meshes, orthophotos and digital elevation models.
Modern close-range photogrammetry using consumer digital cameras and software like Agisoft Metashape or RealityCapture has made high-quality 3D capture accessible to heritage documentation projects that cannot afford laser scanning. Accuracy at close range (5–30 m) of 2–5 mm is routinely achievable with careful capture technique and ground control.
Drone-based photogrammetry extends the method to areas inaccessible from the ground, enabling documentation of building tops, roof structures, tall facades and landscape contexts that cannot be captured terrestrially. For South Indian temple documentation, drone photogrammetry has become the standard approach for gopuram survey.
Relevant Standards
- — ICOMOS Principles for the Recording of Monuments (1996)
Questions about Photogrammetry
How is photogrammetry different from laser scanning?
Both produce 3D point clouds of a building's surface. Photogrammetry derives geometry from overlapping photographs using SfM software; laser scanning measures distances using laser pulses and produces denser, more uniform point clouds. Photogrammetry is generally cheaper and better at capturing texture and colour; laser scanning is more accurate, works better in low light, and handles reflective or transparent surfaces that photogrammetry struggles with.
What software is used for heritage photogrammetry?
The most common professional tools are Agisoft Metashape (most widely used globally, USD 3,499 for the professional licence), RealityCapture (per-credit pricing, very fast processing), and Pix4D (subscription, strong integration with drone workflows). OpenDroneMap is a free open-source option suitable for simpler projects.
Guides that cover Photogrammetry
Photogrammetry
Photogrammetry for Heritage Conservation: Methods, Workflow, Software and Best Practices
Read guideHeritage Documentation
Heritage Documentation: A Complete Guide to Recording Historic Buildings and Sites
Read guideReality Capture